Direction controllable lighting units are known and used e.g. in lighting for entertainment purposes, such as in nightclubs and theatres. In the present context, the term “direction controllable” will be used to refer to lighting units which have a directed light emission, i.e. that has a specific direction as opposed to isotropic light emission (e.g. spot lights), where the direction of this light emission is automatically (non-manually) controllable.
WO 2007/072314 discloses a lighting system with lighting units in light fixtures and a remote control device. The remote control device transmits via a transceiver therein a signal. Upon receipt of the signal, the light fixtures transmit response signals. The remote control may then be used to control various parameters of the nearest light source, such as the beam direction thereof, e.g. by control of a motor or filter device for pan and tilt operation. Further, the remote control calculates its location or distance relative to the light fixtures, e.g. through triangulation, signal strength, time of flight or beam direction. The communication over the transceiver may be radio, such as e.g. Zigbee or Bluetooth, but could also be an RFID or ultrasound tag. The remote control may be configured to control the directivity of the lamps towards its location, e.g. by changing direction.